What OS versions does Tabular support / will support for my OS version be added?

Due to the extra time investment involved in developing and
testing for multiple OS versions, the latest versions of Tabular
will generally only support the most current version of OS X and
iOS. If you can't or do not want to upgrade your OS, you will be
able to continue using Tabular, but you'll stop receiving new
updates.

As a small developer, supporting multiple OS versions is a
significant time investment that detracts from time that could be
spent adding features and fixing bugs. Requiring the latest OS
versions also allows us to much more easily adopt its new
features.